The flying monkeys got me...

Helis and fixed wing

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Thursday, February 2, 2012

eHawk Wing Grows a Pair

My Thunder Tiger eHawk 1500 met its demise on its first flight within seconds of launch. It rolled and had no aileron authority to come back upright before coming hard into contact with the earth. This shattered her fuse-pod and that was about it. I lost the post crash photo... the tail boom snapped off the pod, the motor mount was forced back into the pod, and the forward part of the pod that connected to it was toothpicks. I am rebuilding it (Thunder Tiger via Tower Hobbies special order for $70 plus S&H from Thunder Tiger to Tower Hobbies then to me, my ass...) and will post those pics when I'm damn good and ready.

Back to the wing. The stock eHawk has a single servo driving individual crank control arms, which you can see in the build blog entry above. It sucked from square one, and I had to dicker with it to get it to work. The control throws were within specs, but seemed too small to me, It also seemed to move the inner end of the aileron more than the outer as the aileron twisted along its length. And flight proved this. Others had dealt with this same series of issues and had put the ailerons on their own servos out on the wing. So I decided on this go around to give the eHawk a pair, and it went pretty damn good, if I do say so myself!

I used salvaged generic 9g analog servos. cut the cote over the servo site and ended up pulling it off inward as there was no way I was going to get the servo wires passed to the center otherwise. The servo just sits in that spot.

Long view. One wire was long enough, the other has a 45 cm extension joined with floss (servo connector holder thingy was too bulky to sit in the wing spar where it would be).

Recoted. The cote was pulling away from the aileron, so I replaced it with clear where it wrinkled. I used clear cote on the wing. The white over the servo is sheet balsa coted with white Econocote to give it strength and color. I beveled the edged as it sits on top of the servo and a drop of Beacon 3-in-1 holds the servo to it. The square is CA'd to the wing. Not optimal if I need to replace the servo...

Close up. Clean, works excellent on a servo tester with great throw. NOW she's got ailerons!

Wing looks good! I should have the pod done, and the whole thing put back together by next week. Hope to fly her next week, well this time...

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